Three-part artificial foot(lateral motion and ankle rotation)



J ufly 5, 1949.

J. G. CATRANIS THREE-PART ARTIFICIAL FOOT (LATERAL MOTION AND ANKLE ROTATION) Filed Dec. 11, 1947 2 Sheets-Sheet l INVENTOR. Jojm G. Caz/{11171115, BY Q IM WM y 1949 J. G. OATRANIS 2,475,373 THREE-PART ARTIFICIAL FOOT (LATERAL MOTION AND ANKLE ROTATION) Filed Dec. 11, 1947 2 Sheets-Sheet 2 I V 2 1",, T 3 1 {5 A-/ II Patented July 5, 1949 T lr'iBEE-PART ARTIFICIAL FOGT (LATERAL MQTKUN AND ANKLE ROTATIGNQ John G. Catranis, Syracuse, N. Y.

Application December 11, 1947,'Serial No. 791,128

3 Claims.

This invention relates to feet for artificial legs, and has for a general object a flexible foot structure consisting of flexibly connected sections so located and connected as to provide equal distributlon oi the load, or weight, of the amputee when applied to the leg and foot during the walking cycle.

More specifically, it has for its object a foot structure consisting of an upper tarsus section which isswiveled, or pivoted, on an upright axis to the artificial leg structure, or the tibia thereof, a lower tarsus section hinged to the upper section by ahorizontal forward and rearward pivot joint, a metatarsal section pivoted to the lower tarsus section on a transverse horizontal axis, and a pha'langes section pivoted to the metatarsal section on a transverse horizontal axis, together with resilient yielding means, as rubber blocks, located to resist relative swiveling action of the leg structure and the upper tarsus section, the relative pivotal action of the lower and upper tarsus sections, the relative pivotal action of the lower tarsus and the metatarsal sections, and the relative pivotal action of the metatarsal and the phalanges sections.

The invention consists in the novel features and in the combinations and constructions hereinafter set forth and claimed.

In describing this invention, reference is bad to the accompanying drawings in which likecharacters designate corresponding parts in all the views.

Figure 1 is a side elevation of this artificial foot, the contiguous portion of the leg structure being also shown.

Figure 2 is a plan view of parts seen in Figure l, the fibula part being omitted.

Figure 3 is a sectional view on line 3-3, Figure 2.

Figure 4 is a sectional view taken on line 4 4, Figure 2.

Figures 5, 6, and 7 are sectional views on lines 5-5, 66 and 1-1, respectively, Figure 4.

"The numeral i designates the upper tarsus section, 2 the lower tarsus section, 3 the metatarsal section, and ii the phalanges section.

5 designates the contiguous portion of the upper leg structure. This may be of any suitable construction, that here shown includes upper and lower frame or tibia parts 5 and 1, the latter being mounted on a transverse ankle pivot 8, and having an upright hearing at 51 extending crosswise of, and to the rear of, the ankle pivot -8, in which bearing is mounted an upright pin H1 carried by the upper part 6 and swiveled in the 2 bearing 9. A block -H, of resilient material, is mounted in opposing sockets l2 and E3, in the parts 6, l, to yieldingly "restrain the relative swiveling movement of the leg structure and the foot.

The upper tarsus section 'I is in the general form of a shallow box, and the lower .part 1 of the leg structure and the ankle pivot 8 is located within the box formation. Theankle pivot 8 is mounted between upright lugs it within the tarsus section i.

ifi designates a "fibula link of the leg structure, this being pivoted :at 1 6 to the upper tarsus section "i within the same. The construction and operation of the leg structure forms no part of this invention and is pertinent only insofar as the foot action is concerned-due to the swiveling of the upper leg to the foot structure, or the upper tarsus section I.

The upper tarsus section I is also formed with bearing lugs I7 and 18 depending into the lower tarsus section :2, and in which lugs are mounted, a forward and rearward extending spindle or shaft 19 "on which a bearing block 20 within the lower tarsus is mounted so that the upper section 5 has a lateral pivotal movement about the axis of the spindle. The metatarsal section 3 is connected to the forward end of the lower tarsus section 2 by atransverse horizontal pivotal joint 2'! to have a flexing or pivotal movement relatively 'to the lower tarsus section 2 and to the upper tarsus section i. The phalanges section is pivoted to the front end of the metatarsal section by a transverse horizontal pivot at 23, the sections :i and *3 being spaced to permit the pivotal movement of the metatarsal section, and the metatarsal and phalanges sections being spacedto permit'rel-ative pivotal movement thereof about their horizontal pivots.

The joint of the lower tarsus section, that is the pivot i9 provides for a lateral motion (inversion and eversion). The metatarsal pivot or joint '21 provides shockabsorbing characteristics, as will be hereinafter described, either when standing, or walking, and the joint 23 between the metatarsal 'and pha'langes sections provides for toe flexing. These three sections provide for progressive dorsifiexion and progressive lateral motion from the heel to the toe while the leg is hearing the load of the amputee. This action provides a more'equa'l distribution of load on the plantar surface during the walking cycle while the foot maintains either .a constant or varying outwardly rotated position.

The lower tarsus :section Zis provided with forwardly extending hinge leaves 24, Figure 6, which extend between and are paired with rearwardly extending hinge leaves on the metatarsal section 3. Hinge pins 26 extend through each pair of hinge leaves 25, 24. The lower tarsus section, or the block 20 thereof, is also provided with a forwardly extending shoulder or flange 21, Figures 4 and 6, which extends between the ends of the hinge pins 26, and a cushioning strip 28 is located between this flange and a rearwardly extending complemental flange 29 on the metatarsal section 3, the flange 29 extending between the hinge leave 24. The sides of the sections of the foot are rounded to conform to the general outline of a natural foot, the metatarsal section being so rounded, as shown at 30. The metatarsal section 3 is provided with forwardly extending hinge leaves 3|, which extend between and are paired with rearwardly extending hinge leaves 32 on the phalanges section 4. Hinge pins 33 extend through each pair of hinge leaves 32, 3!. The metatarsal section 3 and the phalanges section 4 are also formed with forwardly and rearwardly extending flanges 34, 35, respectively, extending between the hinge leaves, and between the flanges 34, 35, a cushioning strip 36 is located.

The yielding resilient means, or blocks, in addition to the block I! for resisting the swiveling movement of the upper leg, and in addition to the cushioning strips 2| and 36, includes a resilient member 31 interposed between the upper tarsus section and the metatarsal section to resist the pivotal movement of the upper tarsus section about the spindle or shaft [9, and also resist the relative pivotal movement of the sections about the pivot pins 26, and also a similar member 38 between the metatarsal section and the phalanges section to resist movement about the pivot pins 33.

The member II, as seen in Figures 2, 3 and 4, is an oblong block of rubber, or similar material, extending horizontally so as to be compressed endwise during turning of the upper leg structure about the axis of the upright pivot Ill. The member 3'! is a cylindrical block of rubber, or similar material, extending into sockets 4i] and 4i in the opposing ends of the upper tarsus and the metatarsal sections, this block taking compression during relative pivotal movement of the 4 upper tarsus and metatarsal sections toward each other, and also a relative lateral movement due to relative movement of the upper and lower tarsus sections and the metatarsal section with the lower tarsus section about the spindle or shaft I9.

The member 38 is an oblong block of rubber extending into a socket 42 in the front end of the metatarsal section and extending across the space normally between the metatarsal and the phalanges sections and receiving compression during relative movement of the metatarsal and phalanges sections about the pivot pins 33. There is also a shock absorbing cushion 43 within the rear end of the upper tarsus section coasting with a rearwardly extending flange 44 on the bearing block I of the upper leg structure for the upright pivot 10. This part 43 is merely to cushion the shock during the walking operation when the heel of the foot comes down on the walking surface at the end of a forward step taken by the artificial leg.

Also, there are cushioning blocks 45 and 46 located to cushion the lateral swinging of the upper tarsus relatively to the lower tarsus about the spindle or shaft l9, these being located between the upper and lower tarsus sections to restrain the tilting of the upper tarsus section relative to the lower tarsus section. There is a recess 47 in the sides of the upper and lower tarsus sections in which recess the cushion 45 is located, and the cushion 45 is in two sections at the front end and the rear end of the recess. The recess is for the purpose of providing a working space for the lever 48 rigid with and extending rearwardly from the metatarsal section 3. This lever is for operating a knee lock control by the flexions of the sections of the foot, and forms no part of this invention.

If, during the walking cycle and assuming the artificial foot is the right foot, the amputee twists the leg clockwise while the foot is on the walking surface and the weight of the amputee applied to the leg and foot, the leg swivels clockwise about the aXis of the upright pivot I0, thus causing the foot and leg to take a relative angular radial position shown in position A, Figure 2, from the normal straight position B. If the leg is turned counter-clockwise, the leg and foot take a relative radial position shown at C, Figure 2. A turning inward to position A is called inward rotation, and to position C outward rotation.

Owing to the sectional formation of the foot, the swiveling of the upper tarsus section, the hinging of the sections and the yieldingly resilient means, or blocks, opposing the swiveling and hinging movements of the leg relative to the foot and pivotal or hinging movement of the sections, progressive dorsiflexion about the ankle joint and progressive lateral movement is provided for from heel to toe during the walking cycle and while the weight or load is being applied to the artificial foot. Also the load is distributed substantially equally on the plantar surface while the foot maintains a constant or varying rotated position.

What I claim is:

1. An artificial leg and foot, the foot including upper and lower tarsus sections, the lower tarsus section being pivoted to the upper tarsus section by a forwardly and rearwardly extending pivot permitting relative lateral movement of the upper and lower tarsus sections, a metatarsal section hinged to the front end of the lower tarsus section by a transverse pivot, a phalanges section hinged to the front end of the metatarsal section by a transverse pivot, a resilient member between the metatarsal section and the upper tarsus section to resist relative lateral movement of the tarsus sections and the metatarsal section, and a resilient member between the metatarsal and phalanges sections to resist pivotal movement thereof.

2. An artificial leg and foot, the foot including upper and lower tarsus sections, the lower tarsus section being pivoted to the upper tarsus section by a forwardly and rearwardly extending pivot permitting relative lateral movement of the upper and lower tarsus sections, a metatarsal section hinged to the front end of the lower tarsus section by a transverse pivot, a phalanges section hinged to the front end of the metatarsal section by a transverse pivot, a resilient member between the metatarsal section and the upper tarsus section to resist relative lateral movement of the tarsus sections and the metatarsal section, and a resilient member between the metatarsal and phalanges sections to resist pivotal movement thereof, the leg structure including upper and lower sections and an upright swivel connection between the same, the lower section being pivoted by a transverse ankle joint to the upper tarsus section, and a yielding resilient member between the swiveled sections to resist swiveling movement thereof.

3. An artificial leg and foot, the leg including upper and lower sections connected by an upright swivel joint, the foot including an upper tarsus section connected to the, lower section of the leg by a transverse horizontal ankle joint, a lower tarsus section hinged to the upper section by a forwardly and rearwardly extending horizontal pivotal joint permitting relative lateral swinging movement thereof, a metatarsal section hinged by a transverse pivot to the front end of the .lower tarsus section, a phalanges section hinged No references cited. 

